Crash cushions may be used alongside highways in front of obstructions such as concrete walls, toll booths, tunnel entrances, bridges and the like so as to protect the drivers of errant vehicles. Various types of crash cushions may be configured with a plurality of energy absorbing elements, such as an array of resilient, self-restoring tubes, which facilitate the ability to reuse the crash cushion after an impact. The tubes 2 may be exposed, as configured for example in the REACT 350® impact attenuator (FIGS. 1A and 1B; see also U.S. Pat. No. 6,554,429) manufactured by Energy Absorption Systems, Inc., the assignee of the current application, or disposed within bays 4 defined by a plurality of diaphragms 6 and fender panels 8 extending alongside the diaphragms, as shown for example in the QUADGUARD® Elite crash cushion (FIG. 2), also manufactured by Energy Absorption Systems, Inc. In these types of systems, the tubes may be made of high density polyethylene. As shown for example in U.S. Pat. No. 6,554,529, some of the tubes incorporated into such crash cushions may be configured with a compression element disposed inside the tube so as to resist compression during a lateral impact. The compression element may be secured to the tube with a hinge portion. The compression elements may limit the total compression stroke of the tube in which they are deployed during an axial impact, and further are used in connection with systems having a width defined by more than one row of tubes.
In order to meet certain crash test standards set forth in the National Cooperative Highway Research Program Report 350 (NCHRP-350), including without limitation the Test Level 3 (TL-3) requirements, some crash cushions may require a minimum overall length or a minimum number of tubes so as to satisfy the energy dissipation requirements. These parameters may add to the overall cost of the system, and/or may limit the ability to deploy the system in certain environments having various spatial constraints. Thus, the need remains for reusable crash cushions that meet the NCHRP-350 requirements, but are relatively short in length.